1. Field of the Invention
The present invention relates to a camera supporting the advanced photo system, and more particularly, to a camera being small in size and having minimum functions necessary for the new photographic system.
2. Description of the Prior Art
In recent years, a new photographic system called advanced photo system (hereinafter, referred to as new system) has been introduced, and cameras and films supporting this system have been commercialized. This system has been spreading because it is superior to the conventional system using the 135 film in camera size reduction and convenience in photographing.
First, a film supporting the new system will briefly be described. FIGS. 1 and 2 are perspective views of a film cartridge for the new system (hereinafter, referred to as cartridge 1) viewed from above and below, respectively. A film 10 is housed being wound around a rotatable spool 3 in the cartridge 1 and the spool 3 can receive rotation from a driving system of the camera by a subsequently-described spindle key being engaged in a key groove 3a formed in the spool 3. A light lock door 6 is provided at a film outlet 5. A subsequently-described opening and closing key of a predetermined configuration is inserted into a key hole 4 having a locking portion 4a and a rotary portion 4b, and is rotated in the key hole 4, so that the light lock door 6 is opened. This enables the film 10 to be sent out.
On the side of the upper surface 1a of the cartridge 1, a data disk 2 rotatable integrally with the spool 3 is fixed. On the data disk 2, film information such as the number of exposures and the ISO speed of the film is recorded by means of a bar code 2a. The film information can be read out by an optical sensor provided in the camera. At the lower surface 1b of the cartridge 1, marks 7 ("unused" 7a, "exposed partway" 7b, "fully exposed" 7c and "developed" 7d) representing the film use condition are provided. The film use condition is indicated by one of the marks 7 being displayed in white according to the stop position of a white indicator 8 rotatable integrally with the spool 3 (in FIG. 2, the film use condition is "unused" 7a).
Since the relative positions of the indicator 8, the bar code 2a and the key groove 3a are fixed, the position of the indicator 8 can be recognized by the optical sensor for reading out the bar code 2a or a mechanism for detecting the position of the subsequently-described spindle key rotatable integrally with the key groove 3a. The operation of stopping the indicator 8 at one of the positions of the "unused" 7a, the "exposed partway" 7b, the "fully exposed" 7c and the "developed" 7d will be called VEI setting (VEI is an abbreviation of "visual exposure information").
In a typical camera supporting the new system, as shown in FIG. 3, a cartridge chamber 21 where the cartridge 1 is loaded is disposed on one side of a camera 20, and a cartridge chamber lid 22 for insertion of the cartridge 1 is provided at an end of the cartridge chamber 21. On the other side of the camera 20, a winding spool 26 for winding the film 10 therearound is disposed.
When the cartridge 1 is loaded into the cartridge chamber 21, the light lock door 6 of the cartridge 1 is opened, the film use condition is determined based on the position of the data disk 2, and the film information is read out from the bar code 2a formed on the data disk 2. When the film use condition is "unused", an operation to transport the film 10 to the first frame is necessary. When the film use condition is "exposed partway", an operation to wind the film 10 being exposed partway around the winding spool 26 is necessary. When the cartridge 1 is taken out, an operation to record the film use condition on the film cartridge 1 according to the position of the indicator 8 and close the light lock door 6 is necessary. Since these operations are complicated, automatic control by motor driving is indispensable. At present, winding and rewinding the film 10 by motor driving is a function provided in most cameras. In addition to this function, cameras are desired to have a function to automatically perform an operation to lock and a unlock the cartridge chamber lid 22 in order to prevent the film 10 from being damaged by the user inadvertently opening the cartridge chamber lid 22 during photographing.
An example of operations necessary for the motor driving and other operations will be described on the time series by use of a brief flowchart shown in FIG. 4. In the figure, the operations enclosed by broken lines are manually performed by the user According to the flowchart, first, the cartridge 1 is loaded into the cartridge chamber 21 and the cartridge chamber lid 22 is closed (operation number 201). Then, the cartridge chamber lid 22 is automatically locked (202) and the light lock door 6 is opened (203). Then, the spool 3 is rotated in the rewinding direction, and the position of the data disk 2 and the data on the data disk 2 are read out (204, 205). When the film use condition is "fully exposed" or "developed", the operation shifts to the subsequently-described VEI setting. When the film use condition is "unused" or "exposed partway", the film 10 is sent out (206, hereinafter, this operation will be referred to as thrust driving), it is detected that the tip of the film 10 is caught by the winding spool 26 (207), the film 10 is wound up around the spool 26 until the first frame or the first unexposed frame (208, 209) reaches an exposure portion of the camera and the operation is stopped. These operations will be referred to as initial loading.
When the user turns on a rewinding switch (210), the operation shifts to a subsequently-described rewinding driving. When the user performs photographing (211), winding-up driving is performed by one frame for each photographing (212). When all the frames have been exposed (213), rewinding driving of the film 10 is performed (214), the VEI setting is performed to stop the indicator 8 at a position corresponding to the film use condition and the operation is stopped (215). When the user turns on a switch for unlocking the cartridge chamber lid 22 (216), the light lock door 6 is closed (217) and the cartridge chamber lid 22 is unlocked (216), so that the cartridge chamber lid 22 is openable (219).
A driving mechanism of a camera capable of performing the above-described series of operations is disclosed, for example, in Japanese Laid-open Patent Application No. H9-211590.
In the driving mechanism of this conventional example, a planet gear is provided for each of the operations of winding-up driving, rewinding driving, thrust driving, opening and closing driving of the light lock door 6 (including the cartridge chamber lid locking mechanism), and the operations are controlled by contact between a cam and followers of planet carriers holding the planet gears. For this reason, the number of parts is large, so that size reduction of the camera is difficult and the cost increases.